1. Field of the Invention
The present invention relates to a refractory mortar cured material applied on surface or joint portions of ceramic refractory materials such as fire bricks used in linings of melting furnace or firing furnace used at high temperature.
2. Description of the Related Art
On surface or joint portions of porous ceramic refractory material, refractory mortar cured materials are often formed for the purposes of enhancing the corrosion resistance or mechanical strength by isolating from the ambient atmosphere, adhering, and mending and the like. In such a case, since moisture is absorbed in the base material when the refractory mortar is applied on the base material surface or joint portions, a local shrinkage difference occurs in the refractory mortar cured material, and fine cracks may be generated. Besides, when the moisture is absorbed in the base material, the viscosity of the refractory mortar is raised, and the coating performance may be lowered.
To solve these problems, patent document 1 discloses a material containing powder and water having tap bulk density of 1.3 g/cm3 or more and average particle size of 20 to 55 μm. The technology in patent document 1 is intended to suppress moisture absorption, and prevent crack or peeling of ceramic material by suppressing shrinkage difference.
Even by this technology in patent document 1, it is insufficient in depression of cracks occurring in initial period of forming the ceramic material or cracks occurring by heating after coating process, and it is not satisfactory from the viewpoint of thermal impact resistance. Generally, cracks are caused when the ceramic material is exposed to thermal stress during drying or heating process, but propagation of cracks may be blocked by pores existing in the texture. However, in the ceramic material in patent document 1, since cracks are not uniform in size and are localized, it is estimated that cracks may not be suppressed sufficiently.
[Patent document 1] Japanese Patent Application Laid-Open (JP-A) No. 2004-231506